The airplane was substantially damaged while ditching in the Hudson River, following a total loss of engine power in cruise flight at 1152 Eastern time. The Private pilot and Flight Instructor sustained minor injuries; visual conditions prevailed for the instructional flight to familiarize the Private pilot with the VFR corridor along the Hudson River. The airplane was in cruise flight at about 900 feet agl when, without warning, the engine sputtered and lost all power. The instructor took control of the airplane and transmitted a distress signal. His attempt to restart the engine was unsuccessful, and he then ditched the airplane in the Hudson River. The New York City Police Department and U.S. Coast Guard rescued the pilots.